Evaluation of moisture indices for management of insulated walls in Canada

Abstract

This study reviews the moisture indices used in moisture management of insulated walls in Canada. The Moisture Index (MI), was reviewed and critiqued for its role in the building code for characterizing different climate regions for moisture management. Further in this study, alternative moisture indices are statistically evaluated based on different factors like precipitation and temperature, dominant wind direction, relative humidity, number of sunshine hours, and degree day as possible alternatives to the MI. A sensitivity analysis was conducted to compare variability in each index in order to compare and to show limitations of each for several different cities in Canada. Results showed that when certain indices were much more sensitive to changing temperature, others were more sensitive to changing relative humidity or rain intensity. Finally, a comparative study was done to compare the different indices for individual cities and to compare different cities for individual indices. In comparative study, a new method of using a hypothetical BOCcity as normalizing factor was used. Some indices showed great variability across the country and some not so much.